Broach



J. OAKLEY.

BROACH.

APPLICATION FILED OCT. 6. I920.

Patented July 25, 1922,

INVENTOR.

yv KAA I kwia M,

A TTORNE Y.

:t-rates still another embodiment of the in- ,vention PATENT orrietq JOHN OAKLEY, or SPRINGFIELD, MAssAoHUsn'rTs.

' BROACE.

Speci fieation of Letters Patent.

Patented July 25, 21922.

Original application filed June 25, 1918, Serial No. 241,748. Divided and this application filed October 6,

1920. Serial No. 415,010.

To all whom it i/iag concern:

Be it known that I, JOHN OAKLEY, a subject of the King of Great Britain, residing at Springfield, in the county of Hampden and State of Massachusetts, have invented a new and useful Breach, of which the following is a specification.

My invention relates to improvements in tools of the drift or broach type, which are used to cut grooves, channels, slots, and the like in various objects, and consists essentially of a shank provided with cutting teeth, and equipped with a pilot ahead of such teeth, together withsuch other elements as may be needed or desired in order that the tools shall be complete and serviceable in every respect, all as hereinafter seet forth.

This application is a divisional part of my application for Letters Patent of the United States, Serial No. 241,748. filed June 25, 1.918, which eventuated in Patent No. 1,359,831, dated November 23, 1920.

The primary object of my invention is to provide a tool of this character with means to guide the same through the work in which a slot or groove has been initially cut or formed, so that the teeth of such tool shall be caused to follow with great accuracy the path of said guiding means, and thus be held to their course without liability of springing so as to tear or otherwise mar the sides of the groove or slot cut thereby, which is of the utmost importance, especially with reference to the leading teeth.

Qther objects and advantages will. appear in the course of the following description. I attain the objects and secure the advantages of my invention by the means illustrated in the accompanying drawings, in which-- Figure 1 is a side elevation of the forwardend portion'of a-broach which embodies a practicalform 'ofmy invention; Fig. 2, a top plan of the same; Fig. 3, a cross section through said broach, taken on lines 3-3, looking in the direction of the, associated arrow, in Fig. 1; Fig. 4, what may be termed a side elevation of the forward-end portion of a broach which illustrates another embodimentof'said invention, and, Fig.5, what may be termed a side elevation of the forward-end portion of a broach that illus- Similar reference characters designate simllar parts throughout the several views.

The teeth and clearance passages in the.

breaches herein illustrated are similar to those described in and covered by the ai'ore said two patents, so that no extended description of the same need herein be given In matters of shape, size, arrangement, and construction of the parts of my invention,'it is to be understood that other modifications, in addition to those illustrated in connection herewith, may be made without departing from the nature or said chine, as a screw-threaded puller-head 2.

the same being partially broken 1' off? in Fig,

5, a plurality of teeth which differ more or less in different broaches, and guiding means ora guiding clementtermed a pilot.

Mounted on the shank 1 of the first broach is arow of flat, rectangular teeth 4;, and a pilot 5. There isa longitudinal, chip-clear 5 ance passage or channel 6 formed in the shank 1 on eachside ot'that part of said shank to which the' teeth i are attached. The teeth 4i overhangthe channels 6'; Said teeth are all of the same thickness and let into the shank .in such a manner as to obtain the stepped arrangement required in broachmg. v ;v i

The pilot 5 is ofthe same width and depth as the Jwidth-and depth of the original slot which the toolis designed to widen; and is located on the shank 1- in advance of the row of teeth 4;, and in the central, lorigitu dinal plane of said row. Thepilot 5 is formed on the outer end of a plug-7 which fits within a recess in the shank, "and." is secured therein by transverse-pin -8 passinn-through said shank and plug.

The central portions of the cutting ed es of the teeth 4, which are in direct line w th the pilot 5, do no cutting, but the outlying portions of said edges cut away the stock to widen the original slot. The chips out by the teeth 4: pass directly into the channels 6 in the shank, and through the latter escape at the rear end. of said shank. That part of the shankwhich, directly supports the teeth t is no wider than the pilot 5, consequently there is nothingto divert the chips from their downward courses against the beveled front edges of said teeth, as soon as said chips are cut, and into the chip-clean ance channels. I

lit is now clear that, if this broach be applied to a piece of stock having a central opening or passage and a slot therethrough, which slot it is desired to widen, and which passage and slot correspond, respectively, to

the diameter of said shank and the size of the pilot 5, said shank will fit said passage and said pilot will fit said slot. Now, if the width of the teeth at corresponds with that of the required slot, and the depth of the rearniost tooth is equal to the depth ofsaid slot, the operation of widening is as follows: The forward end. of the shank 1 is introduced into the passage and the'pilot 5 into the slot in the stock, and the tool. is drawn forcibly through said passage and slot, with the result that the cutting edges of the teeth 4: or the portions thereof that overhang the channels in the shank progressively cut away the inner periphery of said stock both sides of said slot, forming first the inner corners of the enlarged or widened slot, and working radially or outwardly until finally the wide slot complete is produced.

The pilot 5 leads and the teeth 4 follow and cut the new or enlarged slot the full width and deeper and deeper the farther the tool progresses, as is clearly apparent. The chipscut by the teeth on both sides of'the slot are directed by the beveled front edges of said teeth into the passages or channels prepared to receive" them, and said chips pass freely through saidchannels and finally ofl. at the rear end of the tool.

The broach, a portion of which appears in Fig. 4, is a widening tool having three rows of teeth 9 and the same number of pilots 10. although it might have more or less than three rows of teeth and three pilots. A single tooth in each of two rows and two pilots only are represented in the drawing. lVith the triple rows of teeth and pilots three longitudinal, chip-clearance channels 11 (one only appearing in, the drawing) are required, instead of two as in the other breach which has just been described. The exterior faces of the pilots 10 andof the .teeth 9 are convex, because this broach is designed towid'en grooves or' slots which require suclrfaces. but the latter might be flat like-the faces of similar members in the first breach, and, cont-rariwise, the e terior faces of the pilot and teeth of said first broach might be convex.

Each tooth 9 is shaped generally like an arrow-head, and arranged on the shank 1 point forward with the cleft behind. Each succeeding tooth 9 from front to rear is set farther from the axial center of the shank, as in the first case and for the same reason. V-shaped channels 19 for the chips are made inthe shank between adjacent ends of the teeth 9 in each row, and between the foremost ends of the leading teeth and the pilots 10, so that the chips cut by said. teeth pass clear of the latter on both, sides into said channels and thence into the channels 11.

The Fig. +1 breach is designed and adapted to widen three slots in a piece of stock which is capable of receiving the shank of said breach and the pilots 10, the peripheral walls of which slots are concave. The teeth '9 and the pilots 10 conform in shape to the shape of the aforesaid walls, as previously observed. The middle portions of the teeth 9 or the portions thereof that are directly in line with the pilots 10 do no work, but the outlying portions of said teeth or of their cutting edges remove the stock radially and widen the slots.

The breach. a portion of which appears in the last view. is an example of a spiral, widening tool which includes another form of teeth and pilot. There are two, oppositely-disposed. spiral rows of teeth 13 on the shank 1 in this case, and two oppositelydisposed pilots 14;- on said shank, and the outer faces of said teeth and pilots are'convex as in the preceding example, but there might be more or less than that number of rows of teeth and pilots,-such row or rows might be straight, and the outer faces there- 105 of might be fiat. There is a longitudinal channel 15, on one side of each row of teeth 13, in the shank 1, said shank has" two flat tened surfaces 16 upon which said teethare mounted. and there are obliquelytransverse 110 channels 17 in said flattened surfaces between the teeth themselves and between said teeth and, the pilots. each of said channels 17 opening at one end into one of said lon itudinal channels. The channels 15 and die flattened surfaces 16 are spiral, andsaidflattened surfaces have an outward incline from front to rear, longitudinally of the shank. for the purpose of giving to the teeth 13 the difierent required amount of projection. without making said teeth of different thicknesses or setting any of them into the shank. the inner faces of the teeth being beveled slightly to conform to the inclination of said surfaces.

Tnoperation, the pilots 14 first enter the previously prepared slots in the stock, which slots are spiral in the present instance, and the teeth 13 follow and widen and deepen said slots, the chips passing down into the 130 branch channels 17, through the latter into the channels 15, and thence away at the rear end of the broach.

It is an advantage to employ an attachable and detachable pilot (or pilots), such as that represented in the first three views, not only because it is frequently less expensive to construct a broach with such a pilot (or pilots), but on'account of the fact that the same when damaged or broken can be taken out, repaired, and replaced, or replaced with a new one, without being obliged to discard the entire broach. The manner of removing and replacing the pilot 5 will be readily understood from the drawings and hereinbetore given description.

The pilots may be integral with or permanently attached to the shank, as indicated in Figs l and 5 wherein no means is shown for removing the pilots l0 and 14.

lVhat I claim as m invention, and desire to secure by Letters 1 atent, is

1. A broach comprising a shank provided with a row of teeth, and further provided with a detachable guiding member in advance of said teeth.

2. A broach comprising a shank having longitudinal channels formed in the periphery and opening at the rear end of said shank, a row of teeth on that part of said shank which is between said channels, said teeth having outer transverse cutting edges,

and a pilot, of less width than that of said teeth, on said shank ahead of the teeth.

A broach comprising a shank, teeth on said shank having outer transverse cutting edges, and means to guide said teeth into and through a previously formed slot in the stock, such means being narrower than said teeth.

l. A broach comprising a shank, teeth on said shank having outer transverse cutting edges, and a pilot on said shank ahead of said teeth, said pilot being narrower than said teeth. 7

5. A broach comprising a shank, teeth on said shank having outer transverse cutting edges, and a pilot attachable to said shank ahead of said teeth, said pilot being narrower than said teeth.

6. A broachcomprising a shank, teeth attachable to said shank and having outer transverse cutting edges, and a pilot, of less width than that of said teeth, on said shank ahead of the teeth.

7. A broach comprising a shank, teeth attachable to said shank and having outer transverse cutting edges, and a pilot attachable to said shank ahead of said teeth, said pilot being narrower than said teeth.

8. A broach comprising a shank having longitudinal channels formed in the periphery and opening at the rear end of said shank, a row of teeth mounted on that part of said shank which is between said channels, and extending over the latter, and a pilot, of less width than said teeth, on said shank ahead of the teeth.

JOHN OAKLEY.

WVitnesses:

A. C. FAIRBANKS, F. A. GUTTER. 

